This invention relates generally to slide fasteners and is more specifically directed to improvements in or relating to a slide fastener of the type having an emergency opening zone at its intermediate point such that, in an emergency, the fastener can be manually forced open from the zone without need for pulling the slider along the interlocking rows of fastener elements or scoops.
The slide fasteners of the above described type find advantageous use with emergency exits or other closure openings in tents, curtains and like articles. In the event of an emergency such as a fire or earthquake, a finger pressure is to be applied to the emergency opening zone located intermediate both ends of the interlocking rows of scoops, and the fastener is readily openable from the zone by then manually spreading its stringers apart. There is no time wasted in manipulating the slider all along the rows of scoops.
The conventional emergency opening means, however, consists solely of the noted emergency opening zone in which several scoops are nonexistent on each stringer tape and from which the fastener is meant to be forced open in emergencies. The rows of scoops of the fastener, when interengaged by the slider movable therealong, are highly susceptible to disengagement from the zone. The fastener is therefore easy to open accidentally when, in its normal use, a slight transverse pull is exerted on the zone via the article to which the fastener is attached. Unless this vital defect is remedied, the true practical utility of the slide fasteners with the emergency opening means cannot be established.